This invention relates to a playing card which is coded with an arbitrarily chosen machine-readable indicia not visible to the human eye. In one embodiment, a card's face is coded in a unique pattern visible only in the infrared or ultraviolet regions, without being visibly defaced. The coded card is an otherwise conventional playing card formed from a single non-laminated sheet of flexible material ("card stock"), such as paper, preferably coated with a cured latex of an acrylate-containing polymer.
In another embodiment, the card is a laminated playing card comprising an upper lamina of flexible card stock, a lower lamina (base) of the same or another flexible stock, and an intermediate layer sandwiched therebetween. The laminated card is coded in the region between the upper lamina and the lower lamina, which region is referred to as the intermediate layer, in a manner such that an electronic device can identify the value of the card and access whatever other information the code may have been devised to reveal. In a specific embodiment, the code indicates to an electronic "reader" (of the hidden code) what the value of the card is, and where each card in a deck or set of cards is to be dealt without the dealer knowing the identification of the card.
As one skilled in the art will readily appreciate, coding a deck of playing cards, each with a visible (to the human eye) code, for example a standard Hollerith pattern or "bar code", by which each card is uniquely identified, is a routine task. To code a card without the code being visible to the human eye, so that a deck of cards may be read by a machine viewing only the faces of the cards which are passed, face downwards, over the reading means of a machine, without defacing the cards and essentially without regard for the orientation of the card as it is passed over the reading means, is not a routine task.
Coded playing cards coded as disclosed in U.S. Pat. No. 4,534,562 to Cuff et al, were conventionally marked with a binary code along its opposite edges so that the code could be seen by the human eye (read by light in the range of visible wavelengths). Since there was no concern about hiding the fact that the cards were coded the necessity of overprinting the faces of the cards did not arise, and the cards were marked on the side edges.
The face of a package of corn chips provided the substrate which was marked with machine readable information overprinted on human-readable symbology, each with a different type of ink in U.S. Pat. No. 4,889,367 to Miller. The human-readable ink absorbs energy in the visible wavelength, but insufficient energy in another wavelength range to prevent a bar-code reading machine ("reader") from reading the bar code. Such a two-ink printing of a bar code on a substrate was well-suited for a package to be read when passed across a grocery store counter where the laser reading the bar code rotates until it can read the code. However, since the orientation of the bar code is fixed on each of the foregoing substrates in the '367 and '562 patents, the code can only be read in one direction by a reader having a fixed light source.
Moreover, it is difficult to find infrared or ultraviolet-absorptive inks which do not absorb in the visible region, that is, have essentially no color. Though inks having very specific energy absorption and reflection characteristics are commercially available, if only on special order, no suggestion or illustrative example of an infrared or ultraviolet absorbing ink which does not substantially absorb in the visible region, is provided in the '562 or '367 patents. Thus the "invisible" bar code of the '367 patent, in practice, is limited to use on colored substrates, such as a mustard color on a bag of chips, or the brown or blue of other snack foods.
Since playing cards traditionally have their face values printed against a very white background, the prior unavailability of colorless "inks" did not provide a practical solution to the problem. Still further, there is no suggestion in the prior art as to what kind of infrared "ink" would be unaffected by the repetitive shuffling, sorting, and sliding of playing cards, face down on a table, all of which actions tend to scuff the cards and the ink, making it difficult to read the code.
Our playing card uses an essentially invisible bar code which can be read only by an electro-optical reading means which uses light in the infrared or ultraviolet region, as described in greater detail hereinbelow, whether the card is laminated or not.
In the non-laminated card of conventional card stock, the code is inklessly textured or etched into the face of the card. By the terms "textured or etched" (which terms are used interchangeably herein) we mean that the surface is either scuffed (or etched) so that the fibers of the card stock are disrupted (typically raised) relative to the fibers which have not been scuffed; or, the surface is impregnated without using a pigment (such as are used in inks), but using a dye or microscopic powder which has essentially no pigmenting value. In either case the surface of the card is said to be "textured". By "inklessly" we mean without using a pigmented liquid or paste used especially for writing or printing. Inkless writings include the symbols on the screen of a compuer's monitor or on a television tube, script or other symbols cut into stone or other durable surface, and messages in smoke written across the sky, inter alia.
For the first time, we have now been able to provide a playing card of card stock which can be marked all over the card's face, if so desired, then overprinted with the face value of the card without visibly changing the "normal" appearance of the card, or vice versa changing the sequence of operations. The unexpected result of being able to code a playing card essentially invisibly by texturing or etching, is that the face of the card may be textured or etched with the code repetitively, or the intermediate layer may be textured or etched with the code repetitively, thus enabling the card to be read in any generally lateral orientation whatsoever, as long as it passes over, preferably in contact with, the machine which reads it. Of course, the card may also be textured or etched with the code in such a manner that the reader will read the code in any generally fixed direction (say along the horizontal x-axis), whether the card is introduced to the reader from either end along the axis.
More preferably, the card is laminated, as stated above, and only the intermediate layer carries the code imprinted on it. As in the case of the non-laminated card, the intermediate layer may be printed with the code repetitively, thus enabling the card to be read, as before, in any generally lateral orientation whatsoever, as long as the card passes over the machine which reads it. And, as before, the card may also be read in any generally fixed direction, if the option or flexibility of presenting the card in an arbitrary lateral orientation is not desired.
More generally the laminated embodiment of this invention relates to providing a machine-readable code in a standardized document such as a credit card, executed original contract, warranty deeds, bearer bonds, passports, credit cards, identification cards and the like. For example, the ubiquitous "plastic card" made according to this invention, may have a code hidden within it which is relatively non-susceptible to wear because it is protected by the upper and lower laminae which have specified optical properties, described in greater detail herebelow. The upper and lower laminae are self-supporting sheets of material which serves as the top and base layers, respectively, of the laminated card.
The term "lamina" is used to emphasize the fact that the sheet is self-supporting and of appreciable thickness, at least about 0.5 mil (0.0005 inch) thick. The terms "top layer" or "upper layer" and "base layer" or "lower layer" are used synonymously with "upper lamina" and "lower lamina" herein only because the former terms are less awkward and more familiar than the latter. The term "intermediate layer" refers either to a selectively reflective non-self-supporting layer typically less than about 0.5 mil thick, or a combination of the non-self-supporting layer with a supporting layer the optical properties of which are immaterial. A non-self-supporting layer, typically consisting essentially of solid particles from 0.1.mu.m-5.mu.m (micrometer) may be sputter-coated or vacuum deposited; particles up to 44.mu.m in average size may be conventionally deposited; while films less than 0.5 mils (0.0005") thick, say from 10.mu.m to formed by known means. A non-self-supporting intermediate layer less than 0.0005" thick may consist of only the particles which define the code, or such particles supported on a thin film of material, preferably a polymeric film.
The face of the upper layer of the standardized document carries the human-readable insignia and comprises a selectively reflective lamina, substantially fully light-reflective in the visible, and substantially transparent (light-permeable) in the infrared or ultraviolet regions. The electrical conductivity of the upper layer is irrelevant, as is that of the base layer, provided such conductivity, if present, does not interfere with operation of the device used to read the coded intermediate layer of the laminated card.
Though the principles upon which the interaction of the components of the laminated standardized document, and more specifically, of the laminated playing card, are well known in optical physics, the choice of the components with a view to their desired interaction is unique.
The device to deal a deck of cards so that a preselected "hand" stored in the memory of the device, is dealt to each player, and to do so in an error-free, repetitive manner, has been disclosed in the parent case. Since the reader (device) is for use by groups of card-playing enthusiasts, it was essential, under the circumstances, that the device be affordable to such groups. The affordability of the device is also an advantage in those situations where standardized documents other than a playing card, are to be read.
The matter of economics for card-playing groups is of particular importance because the game of Contract Bridge is played by a large segment of the population of the world, and the typical person in such a group is not in a position to pay much for any device with which he may practice playing preselected hands, or one he uses to teach himself how to play the game more astutely, or to participate in the game of Duplicate Bridge.
Duplicate Bridge is played in essentially the same manner all over the world as a test of skill in a game in which the same deal is played more than once at different tables. Thus it becomes important that many decks of cards be dealt in preselected sets of 13 cards each to each set of competitors.
It will now be evident that the apparatus and coding system of this invention can also be used to deal hands in the game of poker, or any other card game in which specific cards are to be dealt to a specified location according to directions provided by the memory of the device.
The device is particularly useful as a teaching device because an electronic "chip" can be provided with "teaching hands", and the level of the game being taught can be tailored to the expertise of the learner by simply replacing one chip with another.
Further details for playing the game of Duplicate Bridge, or any other card game where a deck of cards is to be dealt in a prescribed manner, are not of particular importance here. The thrust of this invention is that, in its most preferred embodiment, it provides a playing card which can be read by a device for manually dealing a deck of cards, or any portion thereof, in a preselected manner, by simply sliding each card, face down, across a surface in which electrooptical reading means to identify the card, and means to match the identification of the card with an instruction in the device's memory, result in a signal being given to the dealer as to where (which location) that card is to be dealt.